Heat pump aggregation, optimization and control

One tenth of anthropogenic greenhouse gas emissions are caused by heating and cooling buildings. Efficient electric heat pumps could significantly reduce these emissions, but face barriers to adoption related to costs, equipment selection and installation, and other factors. The goal of this thesis is to reduce emissions by lowering barriers to heat pump adoption. To this end, we investigate heat purchase agreements (HPAs), a new model of heat pump ownership, and develop supporting methods. In an HPA, users host heat pumps owned by an aggregator. The aggregator buys the heat pumps' electricity and sells their heat or cooling output to the users. We show that HPAs can lower barriers to adoption and benefit both the aggregator and the users. We also develop a method for fairly pricing heat and cooling. An HPA aggregator is responsible for selecting an appropriate heat pump for each user under uncertainty. We develop a data-driven selection method that provides probabilistic feasibility and optimality guarantees, and illustrate the method through simulations. An HPA aggregator operates a fleet of heat pumps. If the aggregator invests in sensing, communication and control capabilities, then they can provide services to the electricity grid by perturbing the heat pumps' power use. We develop methods for co-optimizing day-ahead capacity offers for the two highest-priced services, regulation and spinning reserve. In simulations, each heat pump offers 285--325 W of combined annual-average capacity and earns $25--75 of annual revenue. Providing these services could help grid operators integrate more renewable power, and thereby reduce emissions from electricity generation

Spatial regulation by multiple Gremlin1 enhancers provides digit development with cis-regulatory robustness and evolutionary plasticity.

Precise cis-regulatory control of gene expression is essential for normal embryogenesis and tissue development. The BMP antagonist Gremlin1 (Grem1) is a key node in the signalling system that coordinately controls limb bud development. Here, we use mouse reverse genetics to identify the enhancers in the Grem1 genomic landscape and the underlying cis-regulatory logics that orchestrate the spatio-temporal Grem1 expression dynamics during limb bud development. We establish that transcript levels are controlled in an additive manner while spatial regulation requires synergistic interactions among multiple enhancers. Disrupting these interactions shows that altered spatial regulation rather than reduced Grem1 transcript levels prefigures digit fusions and loss. Two of the enhancers are evolutionary ancient and highly conserved from basal fishes to mammals. Analysing these enhancers from different species reveal the substantial spatial plasticity in Grem1 regulation in tetrapods and basal fishes, which provides insights into the fin-to-limb transition and evolutionary diversification of pentadactyl limbs