Sustainable Energyin Denmark

Desi SaludesHillsborough Community College

dsaludes@hccfl.edu

In June of 2010, a group of students from HCC traveled to Denmark to examine first-hand that country’s energy

strategies.

Denmark is a small country of only 5.9 million people with a land area of 16,640 km2. It has 7,314 km of coastline. No point in the country is further than 52 km from the coast.

US/Denmark Comparisons(2009 Figures)

US DenmarkPopulation 309 M 5.7 M

Area 9,158,960 km2 16,640 km2

Annual Energy Use 99,214 kWHr 42,682 kWHr per capita

Net Energy Imports 27.5% -17.9%

US/Denmark Comparisons

US DenmarkAverage Gasoline Tax ~$0.46/Gal ~$5.00/Gal

Average Electricity Cost ~$0.09/KWH ~$0.46/KWHR

Maximum Federal Tax Rate 35% 59% (>$373,650) (>$70,000)

State/Sales/VAT Rates up to 10% 25%

US/Denmark Comparisons

US DenmarkInstalled Wind Capacity 35,000 MW 3,500 MW

Wind as % of Total 1.25% 20%Electric Production

Wind Power

Denmark is perhaps best known for its wind turbines. Wind power provides over 3500 MW or nearly 21% of all electricity produced in the country. The US is the world leader in wind capacity, however, with over 35,000 MW of installed capacity.

Especially in the North of the country, wind turbines are a ubiquitous sight, both on land and offshore.

Windmill CooperativesSpecial tax exemptions and feed-in tariffs are designed to encourage private individuals and groups of individuals to invest in renewable energy. Typically, several dozen to several hundred individuals will pool their assets and invest in one or more wind turbines. The feed-in tariffs guarantee a fixed price for energy fed into the grid for a period of time, usually 20 years.

Time until payoff on these investments (when the turbine is paid off and all additional revenue is free and clear) is typically 8 – 12 years.

Thermodynamic Efficiency

Conventional power plants are typically about 40% efficient due to Second Law of Thermodynamics restrictions. They vent excess heat to the atmosphere or to local water bodies using cooling towers of cooling canals. Here in Tampa Bay, the Big Bend power plant near Apollo Beach becomes a manatee attraction during the winter due to the warm water ejected by the plant. This thermal pollution has been suspected of causing unhealthy changes in the ecosystem of Tampa Bay. Capturing and using this waste heat can more than double the efficiency of a power plant to 80% – 90%.

Cooling Towers

Cooling Canals

The Turkey Point Reactor Site has 168 miles of canals.

CHP - Combined Heat and Power

CHP plants use the waste heat from electricity generation for other purposes, including domestic and industrial heating. The condensed steam from the power plant is passed through a heat exchanger, where it gives off heat to a separate water circuit which is then distributed through underground pipes to nearby homes and businesses. In Denmark, 60% of households have district heating. The Average cost to the consumer per Btu is approximately 30% of electric or oil heating cost. The large infrastructure costs for these projects are largely subsidized by the federal government, using funds collected via the various energy taxes.

District Heating Pipes - Strudstrupvaerket

This 265 MW coal-fired electric plant provides district heating to 285,000 consumers using over 124 km of hot water distribution pipes throughout the city of Arhus.

Distribution Pipes

Distribution pipes are insulated and buried to minimize heat loss along the transport route.

Home Heating Distribution Pipes

These pipes carry the hot water from larger pipes installed underneath the street into and out of homes and buildings.

Instruments in each home measure flow rate, incoming and outgoing temperature to calculate household energy usage.

This small building contains a natural gas fired generator which produces 1.4 MW of electricity and 2.2 MW of heat for a small town of 350 homes. The system circulates 40 m3/hr of water through 4 km of 150 mm pipes.

Here is the generator that provides the power. For small, rural communities, right-sized units like this are more efficient than bringing in power and hot water from a distant plant.

Denmark is the world’s leading exporter of pork products, with 25 million pigs, or about 5 for every Danish citizen, so there is no shortage of manure.

Using Available Resources

This pork farmer got together with two of his fellow farmers and constructed a small methane digestion plant. Generous government subsidies helped him with the $1.3 Million cost of the plant.

This small methane-fired generator produces 750 kW of electricity and about one megawatt of heat.

The entire operation is monitored and run by a single personal computer.

He expects a pay-back time of 8 years. He was so enthusiastic about his success that he decided to expand his operation to triple its current size.

Using Available Resources

In forested areas, wood chips from selective thinning feed the local CHP plants. In barley growing areas, farmers collect and bale hay to sell to the local CHP provider. Strict size and water content limits assure a uniform fuel source.

Energy from Poop and Guts

The Lemvig Biogas facility transforms manure, fish byproducts, slaughterhouse waste and other agricultural waste into biogas (75% Methane, 25% CO2) for electricity and district heat serving 14,000 households. The Lemvig facility processes over 90,000 tons of animal manure and nearly 80,000 tons of industrial waste annually.

Lemvig Biogas FacilityFermentation Vessels

Biogas Storage Tanks

A small 1.2 MW generator provides all the power to run the plant and provides district heating for the citizens of Lemvig.

Electricity from Solid Waste

Most domestic solid waste in Denmark is burned in special power plants. The garbage is first dumped in a giant pit and mixed by a crane operator to increase the homogeneity. This plant burns 41 tons per hour of garbage at full capacity.

The scale of the power plant is impressive. It burns approximately 240,000 tons per year of domestic waste and produces 236,000 MWh of electricity and 500,000 MWh of heat for district heating.

All operations are controlled via a sophisticated network of computers and sensors which monitor the smokestack and adjust various parameters to maximize power output and minimized emissions.

Look familiar? Yes, it’s LabVIEW! (Danish version)

Wave Energy

The Wave Star device in final prototype form. This 2-pad device generates an average of 750 kW.

Wave Energy

The actuator pads are 5 m in diameter.

Wave Energy

The final installed devices will have 20 pads and generate approximately 10 MW each.

Underground Energy Storage System

The Enopson Company has developed a new heat pump system that uses underground water in the aquifer as an energy storage system. During the summer months, underground water is pumped through heat exchangers and the warmed water is pumped back underground

Underground Energy Storage System

During the winter, the cycle is reversed and the stored warm water is pumped back up through the heat exchangers. Heat is extracted and the cooled water is pumped back into the cold water reservoir. No net water is added or removed.

Underground Energy Storage System

The system offer a total payback time of under 2 years for new construction and 3-4 years for retrofitted buildings.

The Nordic Folkecenter for Renewable Energy is a think tank where researchers from all over the world come to work on designing next-generation renewable energy technologies, from new oil seeds to optimized turbine blade shapes.

Nordic Folkecenter

The first hydrogen refueling station in Denmark was installed for cars that are being tested at the Folkecenter.

Solar panels old and new being tested for efficiency and aging characteristics.

This dome contains a small scale, closed-ecosystem, food production facility.

The two swimming pools contain fish that are harvested to feed the visiting researchers. Water from the pools is circulated to the balcony above where vegetables are grown year round.

Here, Preben Maegaard, founder of the Folkecenter and an internationally respected advocate of renewable energy technologies, speaks to the students about his vision for the future.

Recycling

Garbage pickup is very expensive so most Danes make regular trips to the expansive recycling centers. Appliances, electronics and building materials are all accepted and reused.

Bicycles

Bicycles are everywhere in Denmark. Specially marked lanes crisscross all major cities.In Copenhagen, 37% of all people commute to work by bicycle.

Parking bicycles is convenient because nearly all businesses and government buildings have ample parking areas specifically designated for bicycles.

Like most European countries, Denmark has an extensive public transit system of buses and rail lines that makes car ownership optional for most Danes. This bus in Copenhagen is fueled by biodiesel.

Public Transit

Conclusion Denmark is a very small country that is culturally, socially

and politically very cohesive and homogeneous. I believe that the primary lesson to be learned from Denmark’s approach to energy policy is that regional solutions are best. In a country like the United States, with our very wide cultural, social and political heterogeneity, as well as our vast geographical diversity, solutions to the energy challenges we face will best be handled on a regional basis. Where we have wind, build windmills. Where we have sun, install solar panels. Public transit will probably have the greatest impact in areas where the population density is greatest, like on our two coasts. While we do need a national energy policy that promotes renewable energy sources, regionally appropriate technologies will be the key to our success.

Thank you!Desi Saludes

Hillsborough Community Collegedsaludes@hccfl.edu