Assessment on the feasibility of future shepherding of asteroid resources

Most plausible futures for space exploration and exploitation require a large mass in Earth orbit. Delivering this mass requires overcoming the Earth's natural gravity well, which imposes a distinct obstacle to any future space venture. An alternative solution is to search for more accessible resources elsewhere. In particular, this paper examines the possibility of future utilisation of near Earth asteroid resources. The accessibility of asteroid material can be estimated by analysing the volume of Keplerian orbital element space from which Earth can be reached under a certain energy threshold and then by mapping this analysis onto an existing statistical near Earth asteroid (NEA) model. Earth is reached through orbital transfers defined by a series of impulsive manoeuvres and computed using the patched-conic approximation. The NEA model allows an estimation of the probability of finding an object that could be transferred with a given Δv budget. For the first time, a resource map provides a realistic assessment of the mass of material resources in near Earth space as a function of energy investment. The results show that there is a considerable mass of resources that can be accessed and exploited at relatively low levels of energy. More importantly, asteroid resources can be accessed with a entire spectrum of levels of energy, unlike other more massive bodies such as the Earth or Moon, which require a minimum energy threshold implicit in their gravity well. With this resource map, the total change of velocity required to capture an asteroid, or transfer its resources to Earth, can be estimated as a function of object size. Thus, realistic examples of asteroid resource utilisation can be provided

THE EFFECTS OF SPOT WATER MARKETS ON THE ECONOMIC RISK DERIVED FROM VARIABLE WATER SUPPLY

Water availability in semiarid regions commonly exhibits patterns of extreme variability. Even in basins with large infrastructure development, some users are subject to low levels of water reliability, incurring economic losses during periods of scarcity. More flexible instruments, such as voluntary exchanges of water among users, may help users reduce their risk exposure. Recent changes in the Spanish water Law have given an initial impulse to allow for lease-out contracts of water use rights. This paper analyses, from theoretical and empirical standpoints, the effect that establishing water markets has on the economic risk caused by water availability variations. The empirical study is performed on an irrigation district of the Guadalquivir Valley (Spain) with fair levels of average water availability but a high probability of periods of extreme scarcity. A non-linear programming model is used to simulate irrigators' behaviour and derive water demand functions. Another spatial equilibrium model is used to compute market exchange and equilibrium. These programming models are combined with statistical simulation techniques. It is shown that the probability distribution of profits for a representative irrigator is modified if water exchanges are authorised, resulting in unambiguous risk reductions. Results also suggests that if the market would be extended to several irrigation districts and users, each characterised by different hydrological risk exposure, the occurrence of extremely low benefits events would become more unlikely. In sum, it is shown that exchanging water in annual spot markets allows for the reduction of farmers' economic vulnerability caused by the variability of water supply across irrigation seasons.Resource /Energy Economics and Policy,

Modelling Spot Water Markets Under Uncertain Water Supply

Water availability in semiarid regions usually exhibits patterns of extreme variability. Even in intensively controlled basins, some users are subject to low levels of water reliability, and more vulnerable to periods of extreme scarcity. To reduce their risk exposure more flexible instruments, such as voluntary exchanges of water among users, are required. Recent changes in the Spanish water Law have given an initial impulse to allow for leases of water use rights. Properly designed and monitored, this instrument provides some flexibility to water management, and may increase the economic use efficiency as well as mitigate the adverse economic effects of droughts. This paper looks at the risks and uncertainty dimensions of water markets, which have not been paid much attention in the literature. It analyses, from theoretical and empirical standpoints, the role that uncertainty plays in market participants' decisions and its impact on gains from trade. Two models have been developed to carry out the empirical application. One is a stochastic and two-stage discreet programming model which simulates irrigators behaviour and the other is a spatial equilibrium model to compute market exchange and equilibrium. Water market price endogeneity is solved by an iterative process, which characterise price uncertainty from the results obtained from the spatial equilibrium model. Hydrological risk is characterised at the irrigation farm level through the variation of the water allowances served for irrigation. The application is performed on eleven irrigated farms in a district of the Guadalquivir Valley (Southern Spain. It is shown how water availability uncertainty reduces farmers' benefits because of the fact that they must take ex-ante decisions. However, if market participation is allowed once water allowances become known, even at an uncertain price, the benefit losses are partly mitigated. From a methodological standpoint, these results suggest that the agricultural water market benefits estimates found in the literature may be undervalued as a result of omitting the option to participate in the market in the mix of possible strategies. Exchanging water in annual spot markets allows for the reduction of farmers' economic vulnerability caused by the variability and uncertainty of water supply within an irrigation season.uncertainty, farm modelling, water markets, water supply, Resource /Energy Economics and Policy,

Environmental valuation, ecosystem services and aquatic species

The thesis consists of an introduction and four articles that can be read independently of each other. The common topic is environmental valuation and cost-benefit analysis. The applications relates to the growing concern of invasive species, and to waterpower externalities. In broad terms, all of the articles relates to water management. Article 1: "A Cost-Benefit analysis of introducing a non-native species: the case of signal crayfish in Sweden", assesses the economic impact of introducing the signal crayfish into a Swedish lake. Two scenarios are set up and compared. The first one assumes that there is no introduction of signal crayfish, so that the noble crayfish is preserved. In the second scenario, the signal crayfish is introduced, which immediately wipes out the entire stock of noble crayfish. The values of noble- and signal crayfish populations are measured as present values of their net future revenues. The values are than compared and net benefit of an introduction is calculated. The result indicate that net benefit of an introduction is positive if the intrinsic growth rate or the carrying capacity of the noble crayfish is below 40 % that of the signal crayfish. Article 2: "Assessing management options for weed control with demanders and non-demanders in a choice experiment", estimates the benefits of having a weed management program for a lake in Sweden, and then compares them with corresponding costs. The policy recommendation from a simple cost-benefit rule is to control the weed at some specific sites of the lake. This paper also suggest how to distinguish those that have a positive WTP for at least one of the attributes (demanders) from those that have zero WTP for all attributes (non-demanders). The advantage of the suggested approach is that it facilitates to more clearly distinguish between conditional and unconditional willingness to pay. The suggested approach could also overcome some of the problems in the literature with negative welfare measures. Article 3: "Assessing transfer errors in the benefit transfer method: An application of invasive weed management using choice experiment", tests the accuracy of transferring benefits of a weed management program from one lake to another using choice experiment. The transfer errors are assessed and the convergent validity hypothesis is tested. Estimating the accuracy of benefit transfer for weed management is policy relevant as there are a number of lakes in Sweden infested with the water weed. The convergent validity was rejected for three out of five welfare estimates with a ten per cent significance level. Article 4: "Willingness to pay for environmental improvements in hydropower regulated rivers", assesses the benefits of environmental improvements along hydropower regulated rivers using choice experiments. Remedial measures that improve the conditions for fish, benthic invertebrates and river-margin vegetation were found to have a significant welfare increasing impact. The results can be of value for the implementation of the Water Framework Directives in Sweden, which aims to reform the use of all surface water and ground water in the member states

Asteroid resource map for near-Earth space

Most future concepts for the exploration and exploitation of space require a large initial mass in low Earth orbit. Delivering this required mass from the Earth’s surface increases cost due to the large energy input necessary to move mass out of the Earth’s gravity well. An alternative is to search for resources in-situ among the near Earth asteroid population. The near Earth asteroid resources that could be transferred to a bound Earth orbit are determined by integrating the probability of finding asteroids inside the Keplerian orbital element space of the set of transfers with an specific energy smaller than a given threshold. Transfers are defined by a series of impulsive maneuvers and computed using the patched-conic approximation. The results show that even moderately low energy transfers enable access to a large mass of resources

The Value of Stock Options To Non-Executive Employees

This study empirically investigates the value employees place on stock options using information from the option exercise behavior of individuals. Employees hold options for another period if the value from holding them and reserving the right to exercise them later is higher than the value of exercising them immediately and collecting a profit equal to the stock price minus the exercise price. This simple model implies the hazard describing employee exercise behavior reveals information about the value to employees of holding options another time period. We show the parameters of this model are identified with data on multiple option grants per employee and we apply this model to the disposition of options received in the 1990s by a sample of over 2000 middle-level managers from a large, established firm outside of manufacturing. Exercise behavior is modeled using a random effects probit model of monthly exercise behavior that is estimated using simulated maximum likelihood estimation methods. Our estimates show there is substantial heterogeneity (observed and unobserved) among employees in the value they place on their options. Our estimates show most employees value their options at a value greater than the option’s Black-Scholes value

Risk, uncertainty and the Guide to the Draft Basin Plan

For much of the 20th century, the expansion of irrigated agriculture in the Murray Darling Basin, was treated as a self-evidently desirable objective, to be pursued without excessive regard to questions of economic costs and benefits. Irrigation seemed to offer a ‘droughtproofing’ solution to the risks and uncertainties that plague dryland agriculture in Australia. By the late 1980s, however, the capacity of the Basin to support additional diversions was close to exhaustion. Analysis at the time suggested, in the terminology of Randall (1981) that a move from an ‘expansion’ phase in which resource constraints were relatively unimportant, to a ‘mature’ phase, characterised by increasingly sharp conflicts over access to the resource, was underway. It was hoped that these conflicts could be resolved at low cost through the introduction of market mechanisms. In reality, however, as noted by Quiggin (2008), the actual outcome was a ‘crisis’ phase, in which the possibility of a systemic collapse loomed ever larger. The only feasible response, it has become evident, is a ‘contraction’ phase, in which claims to the resource are scaled back. Attempts to deal with the problems of the Basin through the creation of markets in water rights, minimising the role of governments, began with the communique of the 1994 Council of Australian Governments meeting and was developed more fully in the National Water Inititiative announced in 2004 (Council of Australian Governments 1994, 2004). The NWI was described by the National Water Commission as ‘Australia's enduring blueprint for water reform’, through which ‘governments across Australia have agreed on actions to achieve a more cohesive national approach to the way Australia manages, measures, plans for, prices, and trades water.’In practice, however, the NWI failed to resolve many of the key conflicts associated with the mature water economy. Come conflicts between states arose from the need to deal with different systems of water entitlements. Conflicts also emerged between states and within the Commonwealth over the extent to which trade in water entitlements should (or should not be restricted) and over the possibility of transfers of water from rural to urban use.Murray Darling Basin,

A stochastic multiple players multi-issues bargaining model for the Piave river basin

The objective of this paper is to investigate the usefulness of non-cooperative bargaining theory for the analysis of negotiations on water allocation and management. We explore the impacts of different economic incentives, a stochastic environment and varying individual preferences on players’ strategies and equilibrium outcomes through numerical simulations of a multilateral, multiple issues, non-cooperative bargaining model of water allocation in the Piave River Basin, in the North East of Italy. Players negotiate in an alternating-offer manner over the sharing of water resources (quantity and quality). Exogenous uncertainty over the size of the negotiated amount of water is introduced to capture the fact that water availability is not known with certainty to negotiating players. We construct the players’ objective function with their direct input. We then test the applicability of our multiple players, multi-issues, stochastic framework to a specific water allocation problem and conduct comparative static analyses to assess sources of bargaining power. Finally, we explore the implications of different attitudes and beliefs over water availability.Bargaining, non-cooperative game theory, simulation models, uncertainty

A Stochastic Multiple Players Multi-Issues Bargaining Model for the Piave River Basin

The objective of this paper is to investigate the usefulness of non-cooperative bargaining theory for the analysis of negotiations on water allocation and management. We explore the impacts of different economic incentives, a stochastic environment and varying individual preferences on players’ strategies and equilibrium outcomes through numerical simulations of a multilateral, multiple issues, non-cooperative bargaining model of water allocation in the Piave River Basin, in the North East of Italy. Players negotiate in an alternating-offer manner over the sharing of water resources (quantity and quality). Exogenous uncertainty over the size of the negotiated amount of water is introduced to capture the fact that water availability is not known with certainty to negotiating players. We construct the players’ objective function with their direct input. We then test the applicability of our multiple players, multi-issues, stochastic framework to a specific water allocation problem and conduct comparative static analyses to assess sources of bargaining power. Finally, we explore the implications of different attitudes and beliefs over water availability.bargaining, non-cooperative game theory, simulation models, uncertainty