Energy systems of the future – a mixture of big and small

It is well-known that, by using fossil fuels, we’re stretching the limits of what our environment can deal with. But what is the alternative? We asked Professor Erik Dahlquist at Mälardalen University why we need a new energy system in the future and what it might look like.

The fact that we are dependent on fossil fuels is a big problem, even though we are less dependent on them in Sweden than in many other countries. In the future, however, we need to become entirely free from them – partly because there won’t be any left one day, partly because they have a negative impact on the climate.

Oil will be the first to be used up, since there is least of it, but later there will be a shortage of natural gas and coal, too. The impact of the fossil fuels on our climate can be seen in the global rise of temperature by between half a degree and one degree during the last 100 years, the main cause of which is judged to be the increase of greenhouse gases, primarily carbon dioxide.

- It is hard to say exactly how much of this rise is due to the use of fossil fuels, since the systems are so complex, says Erik Dahlquist. But using the uncertainty regarding the measurements as an excuse for not doing anything is a little like jumping off a high-rise building with a parachute and saying halfway down that “this far it’s gone well, so I won’t care to deploy the parachute”.

In order to avoid jumping from the high-rise to begin with, the energy systems of the future need to be reviewed. Erik Dahlquist is looking optimistically into the future and believes that we can do fine without fossil fuels.

- The population of the Earth can have a good life without fossil fuels, says Erik Dahlquist, but we need proper control mechanisms to get us there before it’s too late.

To begin with, Erik Dahlquist thinks that the energy systems of the future will look different in different countries and that they will be mixes of different technologies. In countries like Sweden we’ll have biomass, but solar power in countries like Algeria and Spain, wind power in countries like Portugal and Denmark, and hydropower in countries such as Norway and Sweden.

Storing energy for days when the sun isn’t shining

For some of these sources of energy, production will go up and down, and we won’t be able to control when production is possible. The sun only shines at specific times each day and cloudiness is what it is.

- In order to even out these imbalances in the production, we need to be able to transport energy from one area to another in the future, says Erik Dahlquist. We also have to be able to shift loads in time, from periods when there is no wind or sun to periods when they generate a lot of power.

Since there’ll be big fluctuations in the availability of sun or wind, for example, new types of energy storage, especially for electricity, need to be developed.

- We’re talking about new types of batteries here, but also other technologies such as flywheels that can store energy or pumped-storage hydroelectricity where water is pumped up when the need for electricity is low and released again when the need increases, says Erik Dahlquist.

In the future, we’ll also see other kinds of pricing models for energy. They will be more complex than today’s systems where we essentially only have fixed or fluctuating electricity prices. Instead, the new systems can imply that it may be more expensive to use electricity on days when there is little sun for solar power or little wind for wind power.

New types of cars and car fuels

The energy systems of the future also have to do with our modes of transportation, where electric vehicles and hybrids will play a bigger role. With a new type of hybrid vehicles called series hybrids, fuel consumption can be reduced to under 0.02 litres per kilometre, which can make biofuels a completely natural alternative to the fossil fuels primarily used today.

Practically the entire world is using natural gas as fuel. The problem with natural gas is that it is nevertheless a fossil fuel that, in the long run, causes the same global warming problems as other fossil fuels, even though a little less than coal for a given fuel unit. Research has shown, however, that it is possible to produce biogas through microbiological processes or high-temperature gasification instead. Besides, there are other alternatives to petrol, such as ethanol from straw and sugarcane.

What biogas and ethanol have in common is that they have very high octane numbers. This means that, in series hybrid systems, you can increase the pressure in the combustion engine and thus improve fuel efficiency. A petrol engine, or Otto engine, could become more efficient than today’s diesel engines under such conditions.

- That’s why there is hope that car manufacturers will develop series hybrids for alternative fuels too, and not only for fossil diesel, says Erik Dahlquist.

For heavy vehicles such as trucks and buses, this is of particular interest, as big batteries will be too heavy. Concerning such vehicles, even trolleybuses and trolley trucks that could use electricity on motorways have been discussed.

- As to purely electric engines, these are most suitable for light vehicles that aren’t used much on country roads, says Erik Dahlquist. 70 percent of all transports are shorter than 50 km, so exclusively electric vehicles are best for cities.

Fuel cells are yet another technology being discussed, but the problem with these is primarily that they require very good fuels such as hydrogen – which is very difficult to store. Fuel cells are expensive, too, but in combination with series hybrid vehicles, fuel cells may become successful in the long run, Erik Dahlquist believes.

New heating methods for our buildings

A large part of the energy consumed goes to heating our residences and offices. That’s why we are witnessing the development of new types of houses and buildings that are constructed so as to require less energy.

On the one hand, we see an increase of so-called passive houses, where there is no active heating system. On the other hand, there are zero-energy houses, where the consumption of energy and the own energy production through, for example, solar cells keep each other the balance over the course of a year. Finally, there are low-energy houses that use less than 50 kWh (kilowatt hours) per square metre and year, which is something of an unofficial norm for the future. Considering the typical buildings of today, which consume about 160-200 kWh per square metre and year, there are huge amounts of energy to save. We are talking about reducing energy consumption by up to 75 percent in the long run.

As a complement, it is also interesting to consider how we can save all kinds of energy. Households today use 16-20 TWh (terawatt hours) per year to heat buildings with electricity, but the same amount goes to heating our buildings indirectly through all our appliances. By choosing low-energy alternatives for e.g. TVs, washing machines, refrigerators and freezers, we can save a lot of energy, though at the same time we may increase our need for heating. In such a situation, the installation of wood and pellet stoves can be an interesting idea to meet heating requirements when it’s really cold. On the other hand, well-insulated houses may need cooling on hot summer days.

Many households are using air-source heat pumps for heating. Today, the problem is that these alone cannot heat a house when it is really cold and they need to be complement with electric radiators. An alternative to this, especially in Sweden, would be small stoves running on biofuels during these cold spells.

- A technology that we at Mälardalen University are currently developing together with Dalarna University, among others, is the so-called TPV technology, says Erik Dahlquist. It combines a stove with a sort of solar cells, which means that heat radiation is immediately turned into electricity. It can be interesting to combine this with regular solar cells, except that TPV is used to produce heat and electricity in the winter, when the need for heat is greatest and the sun is conspicuous by its absence, while regular solar cells are used when the sun really does shine during the warmer half of the year.

Adopting new technical solutions means high investment costs, which can be difficult to explain to households. That’s why Erik Dahlquist believes that pricing will be an important factor in channeling energy consumption. In general, it will be very interesting to use electricity prices for shifting loads from periods when production is difficult to periods when there may even be a surplus of solar and wind power. However, to raise high electricity prices even further in wintertime is controversial, and political decisions are needed to achieve a change.

- New pricing models for energy consumption is yet another area where research is carried out at Mälardalen University, says Erik Dahlquist. We are trying to develop and test different pricing models based on probable energy systems of the future, with a lot of sun and wind but reduced importance of nuclear power.

Companies guzzle energy

Not only private homes, companies too use plenty of energy, but there are great economic profits to be made for them through increased energy efficiency.

- In paper production, steel mills and the engineering industry we could save tens of TWh per year through increased energy efficiency, but the problem is that such investments take several years to yield a return, so it is difficult to argue for them unless there is a lot of capital in the money box, says Erik Dahlquist.

It’s become clear that political guidance is important in such contexts. Previously, there was a support program at the Swedish Energy Agency that offered tax reduction to companies that invested in energy saving. The result was that more than one TWh per year was saved.

An equation that does have a solution

The idea that “many drops make an ocean” seems to be one of the main components of the energy systems of the future. We need many technologies that complement each other, but the question is whether that is enough.

Taken together, we have access to almost 9000 TWh of clearly renewable energy in the EU today – through biomass as well as wind, hydro- and solar power. Of these, biomass constitutes the biggest resource with about 8500 TWh. Add to this another 1000 TWh of nuclear energy, which is not renewable, but at least doesn’t affect the climate. If, in the future, we were to promote the development of biofuel production, we could probably increase it by 20-30 percent, which would result in an increase of the total available energy to about 12,000 TWh per year.

In total, we have a primary energy need of 16,000 TWh per year in the EU. Erik Dahlquist thinks that within the EU, we can save up to 4000 TWh per year in connection with the heating of buildings, lighting, reduced food waste, more efficient transports, and increased efficiency in companies. This would lead to energy requirements of 12,000 TWh, and if we compare this with the total amount of available energy, we would achieve a balance.

- At Mälardalen University, we carry out these types of analyses in order to get the big picture, says Erik Dahlquist. For each aspect, we also do in-depth analyses in cooperation with various Swedish and international partners.

In close cooperation with industry

Mälardalen University is cooperating with, among others, Automation Region and different industrial companies to investigate how existing processes can become more efficient, so that energy use is reduced and production increased. The University is also working together with other universities to develop the energy processes of the future, including gasification technology, biogas production and water purification systems, as well as energy-efficient buildings.

- As to the housing of the future, we are involved in the development of new systems where solar energy is integrated in buildings in an effective way, but smart homes, too, is an area of development, says Erik Dahlquist. This is related to the new pricing models, but also new technology for coordinating and controlling the turning on and off of different appliances, conveying information about energy use, and relating the control to the pricing models.

When it comes to energy engineering research, Mälardalen University is at the cutting edge with its expertise concerning application areas and applied mathematics. The University’s researchers within energy and environmental engineering cooperate with researchers in mathematics and applied mathematics in order to develop advanced mathematical models that can solve, for example, optimization problems and provide support in decision-making. That is quite a unique combination, which leads to both advanced functions and robust systems when they are implemented in cooperation with industrial partners. And it is precisely its cooperation with industrial companies that provides the University with a good idea of real-life problems.

- Real problems lead to useful solutions, says Erik Dahlquist. That is why cooperation between university and industry is so important.