Derivados Climáticos

Buildings use energy for controlling the indoor climate and to operate many different electrical appliances. Smart tech- nologies in the built environment can reduce overall energy use, cut bills by using energy when cheapest, improve con- sumer comfort, and support a sustainable way of living. Indoor climate is controlled most effectively through the design of buildings at the beginning of their lives; once the building is complete, changes are difficult and expensive.

This section therefore addresses only how to control the times during which appliances operate – an area that can be influenced relatively quickly and easily through modern ICT.

Electrical appliances should ideally operate so as to mini- mize total consumption and – equally important – use electricity when excess capacity is available and the market price low. Changes in the timing of electricity consumption can save customers money, and can have even bigger bene- fits for power companies and society by reducing peak loads and avoiding the need for new power lines. Household customers have a big influence on peak demand. Figure 38 shows that during the peak that occurs on late winter afternoons in Denmark, households account for about half of all the power used.

Opportunities for domestic consumers to change their con- sumption profiles are limited, and there would be little incentive for them to react to hourly market prices even if they had this information. This is because in Denmark the market price of electricity accounts for only about a quarter of the average domestic bill; the rest covers fixed payments, transmission, public service obligations (PSO) and taxes. Today, although their consumption is metered by the hour, no households have hourly billing.

For enterprises, taxes are much lower and so there is more incentive to use electricity when it is cheap. Even so, only about half of all large consumers (those who use more than 100,000 kWh/year) have hourly billing. This is partly due to the large fees charged by the electricity companies for this service. Hourly billing currently costs around DKK 5,000 a year, so a company using 100,000 kWh/y will pay an extra DKK 0.05/kWh. Since the daily variation in the market price of electricity has a standard deviation of DKK 0.05– 0.1/kWh, a large consumer with a relatively large consump- tion in cheap hours may save money paying an hourly price instead of an average price even without changing his con- sumption. Reducing his consumption in a few very expen- sive hours will increase the profitability of hourly billing, further.

For a typical household using 4,000 kWh/y the current fee for hourly billing is prohibitive, however. For domestic consumption to react to changes in production from inter- mittent sources such as wind power, consumers need better incentives to track and react to the price of electricity, or control technologies that will do this automatically.

Economy Comfort Education Information Reorganization Services Regulation Customer Figure 37

the financial incentive for consumers to change their con- sumption profiles. To allow such a system to create fairly predictable revenues both for the power companies and from taxes, it might be necessary to adjust the percentage each quarter, as Denmark now does with the PSO payment that supports renewable energy. If the percentage is fixed for a year in advance, both tax revenues and consumer bills will fall in wet years (when Scandinavian hydropower is plentiful and power is cheaper) and rise in dry years. This gives unfortunate short-term consumer incentives and may be politically unacceptable.

Another way to create demand flexibility may be to intro- duce dynamic tariffs and taxes. Unlike hourly market pric- ing, dynamic taxes are not optimal from a resource eco- nomic point of view, as taxes should be lump sum in order not to distort the economy. However, dynamic taxes may be justified in terms of existing market failures: the market price reflects short-term marginal production costs, but does not fully take into account long-term costs such as those relating to peak capacity and grid expansion. Replacing part of the current high fixed payments, such as those covering transmission and taxes, with a percentage based on the hourly market price will considerably increase

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Average hourly electricity consumption for Denmark in 2009, arranged by month.

Demand peaks at 5 GW on winter afternoons at around 5.00–6.00 pm. Half of this peak is created by domestic users.119

2009 Residential 2009 Total (GW) 2.5 2.0 1.5 1.0 0.5 0.0 0 3 6 9 12 15 18 21 24 (GW) 6.0 5.0 4.0 3.0 2.0 1.0 0.0 0 3 6 9 12 15 18 21 24

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The complexity of the Danish energy system is increasing: more wind energy, for example, means fewer operating hours for CHP plants, so less heat is available. As a result, energy production is becoming more diversified in both the electricity and heating sectors. Integration between these two sectors is also increasing through the growth of electric water heaters and heat pumps.

Providers of district heating want the return temperature of the water to be low, since this means a larger amount of heat extracted from the outgoing hot water and hence less water to be pumped around the circuit. Furthermore, low return temperatures increase the efficiency of combined heat and power (CHP) plants supplying the district heating grids. The supply temperature, however, should also be low, since this reduces heat losses (which are currently around 20%) and enables use of lower temperature heat sources. These two requirements imply that the equipment in each building should extract as much heat as possible from the circulating water while operating at the lowest possible temperature.

The main objective is to reduce peak loads and hence the need for expensive and often fossil-fuelled peak load capac- ity, as well as facilitating the growth of wind power. This can be done by making smart meters available, by changing regulation and economic incentives and thereby giving households cheap and easy access to the hourly electricity market, or through dynamic tariffs and taxes.