IEEE Power & Energy Magazine - November/December 2019 - 74

Energinet investigates further sector coupling to determine
what a cost-optimized, fossil-free future energy system with
all sectors coupled might look like.
algorithm (blue line). The algorithm uses the EV's operational
flexibility with respect to charging profiles and avoids a negative impact on the available transport service. The result for
the electricity system (yellow line) is a much smoother net
load. Coordination between user and system needs is necessary to avoid voltage and overloading issues. In the United
States, new rate cases that provide an incentive for consumers
to either charge EVs off peak or provide charging deadlines
that support VREs in the system are being explored.

Electricity and Heat: The Economic Benefits of
Integrating Heat and Electricity Sectors

Power (GW)

Flexibility in the heat sector provides excellent opportunities to contribute to the electricity sector's balancing services to reduce system peaks or use excess VRE output by
converting electricity into heat. For the U.K. system, the
related economic benefits can be huge. Technologies such
as CHP, electric heating (i.e., heat pumps and resistive heating), thermal energy storage, and heat networks that link the
heat and electricity systems can provide cross-energy vector
resource flexibility.
Studies using the future U.K. energy scenario with
high RES penetration demonstrate that the investment and
operating costs of a nonintegrated heating and electricity

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2 Feb. 3 Feb. 4 Feb. 5 Feb. 6 Feb. 7 Feb. 8 Feb. 9 Feb.
Net Load
Net Load Including E-Mob
Charging EV

figure 7. The modified net load (i.e., load minus wind and
PV generation) without EV, net load including demand for EV
(trucks and cars) and the load from charging EV for one February example week in Germany. (Source: Fraunhofer IEE; used
with permission.)
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ieee power & energy magazine

system are higher than when both are integrated. The net
benefits of the coordinated operation of heat and electricity systems are between £2.4 and £5.4 billion/year for the
scenario with a carbon target of 100 or 50 g CO 2 /kWh,
respectively. The stricter the carbon target, the higher the
value of resource flexibility.
Given that CHP can provide ancillary services to the
electricity system besides providing heat, a combined cycle
gas turbine plant would be replaced by CHP in the integrated system, saving fuel costs. A higher CHP penetration
leads to reduced industrial network heat pumps capacity
and, consequently, reduces the need to reinforce HV distribution networks.
A deeper decarbonization of the U.K. heating system will
require major electrification. However, there are concerns
related to implications for electricity infrastructure, system operation, and security. To avoid major reinforcement,
hybrid technologies such as hybrid heat pumps (HHPs),
which combine a domestic gas boiler with an air/groundsource end-use heat pump (EHP), have attracted significant interest. Given its hybrid nature, consumers' heating
demands can be met by consuming either gas or electricity,
implying a dual-fuel capability.
The U.K.'s FREEDOM project has demonstrated that
HHP technology can still achieve the environmental potential of a fully electrified heat sector, yet with significant economic savings with respect to a standalone EHP pathway;
the hybrid technology can significantly reduce both upfront
building costs and electricity system costs. Additionally,
HHP technology can save a significant amount of system
costs compared to the stand-alone EHP case (Figure 8). In a
low-carbon system, these gross savings in total system costs
can be between £5.8 and £9.3 billion/year.
HHP technology requires an additional operating expenditure for the gas system as well as additional capital expenditure in low-carbon generation to offset gas emissions by
decarbonizing more of the electricity system. These additional costs are shown as negative benefits in Figure 8. Considering these calculations, the remaining net system benefits of HHP technology are between £4.9 and £7.4 billion/
year. The benefits of HHPs over EHPs are lower in a highly
flexible system, as the operational flexibility from HHPs
competes with other flexibility sources such as controllable
loads (i.e., industrial and commercial loads, EVs, and smart
appliances) and electricity storage.
Both HHPs and EHPs can deliver many valuable flexible
demand-response services to the electricity system. These
november/december 2019

IEEE Power & Energy Magazine - November/December 2019

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