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Low Carbon Power Generation
in Copenhagen
Part of our Low Carbon Copenhagen project ... project index >
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Other technologies
Copenhagen is well on its way to reaching its goal of carbon neutrality by 2025. It's achieving this by using renewable energy technologies such as wind, waste-to-energy, solar, geothermal and biomass — all of which lessen the burden of CO2 pumped into the atmosphere. There are a number of other technologies that are also being investigated.
A wide range of alternative power-generation and application technologies is under development around the world. Here we look at a few that are relevant to Denmark — wave power generation, fuel cell technology, hydrogen as a fuel and electric vehicles.
Wave power generation
Producing electricity using wave power is a technology in development, and Denmark is one of the top five countries in the world working on projects in this field. There are several pilot schemes around the Danish coast, though none near Copenhagen.
At Hanstholm, off the north Jutland peninsula, is a full-scale working wave power scheme set up by Wave Star. It has been generating 500kW since September 2009 and is anticipated to produce some 6MW when complete.
Fuel cell technology
A fuel cell converts chemical energy into electrical energy. A battery is a simple type of fuel cell but there are several kinds (see right hand column). It's not a new idea — Sir William Grove invented a gas voltaic battery in 1839 that produced electricity and water, and the term has been in use since the 1880s.
One current attraction is that fuel cells don't produce pollution as a by-product, just water and heat. And they are efficient at converting energy input into work output. Taking the car as an example, a typical petrol engine is only 20% efficient. A battery-powered electric car is between 26% and 65% efficient, while a car using a hydrogen-powered fuel cell has the potential to be 64% efficient.
Suitable fuels for fuel cells include natural gas, biomass, methane, ammonia and hydrogen. Recently, Risø DTU, the Danish National Laboratory for Sustainable Energy, has been working with Topsøe Fuel Cell (Copenhagen) to develop a ceramic solid oxide version. These could be used in vehicles and ships.
On the 4th January 2010, the 5,900 tonne Norwegian Viking Lady docked in Copenhagen. It's the world's first ship to be powered by a fuel cell — a 320kW molten carbonate cell, running on liquefied natural gas.
Hydrogen as a fuel
Hydrogen is the most common element and one of the most combustible substances — the Sun consists mostly of hydrogen. But how do you harvest it? You can use power to split water molecules into hydrogen and oxygen, but you need a power source to do it. And how do you store hydrogen safely?
In Denmark, on the island of Lolland, they have been using wind-generated electrical current to electrolyse water (separating the hydrogen and oxygen). The wind-hydrogen plant has been in operation since May 2007, one of the first in Europe. The hydrogen they produce is used in fuel cells that run a combined heat and power (CHP) scheme.
Risø DTU has been developing an electrolytic cell that produces synthetic gas (hydrogen and carbon oxide) from water and CO2. The input power can come from wind or solar sources and the CO2 from industrial emissions.
On 12th November 2009, in time for the United Nations climate change summit COP15, Copenhagen opened its first hydrogen refuelling station. It served six hydrogen cars and two vans to begin with but the city fleet is set to increase to 33. Some vehicles used to ferry COP15 delegates ran on hydrogen fuel cells, though they used batteries for short trips.
Electric vehicles
Electric vehicles can be powered by conventional batteries or fuel cells. There are also hybrid vehicles that can combine the reliability of the combustion engine with the environmentally-friendly benefits of electric power.
Copenhagen is expected to have the infrastructure for plug-in charging stations and battery exchanges by 2011. DONG Energy has been testing the feasibility of wind-powered charging stations. The Danish Energy Agency has awarded grants to 19 pilot projects, totalling some 7m Kroner, to get more electric cars onto Danish streets.
The Copenhagen Climate Plan (pdf download) sets out the following initiatives:
— free parking in Copenhagen for electric and hydrogen cars
— bus CO2 emissions to reduce by 25% through use of electricity and hydrogen
— all new municipal car procurement to be electric and hydrogen from 2011
— 85% of all municipality cars to electric or hydrogen in 2015 (600 cars)
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Top links
Renewable Energy Focus   www.renewableenergyfocus.com
Denmark continues its renewable tradition — article on all kinds of renewable enery in Denmark
Copenhagen X   www.cphx.dk
Danish Architecture Centre site on urban development and innovation in Copenhagen
Wave Star A/S   www.wavestarenergy.com
Developers of the wave power generation system installed off Hanstholm
Risø: DTU : National Laboratory for Sustainable Energy   www.risoe.dk
Technical University of Denmark : includes info fuel cell research
European Hydrogen Association   www.h2euro.org
Pan-national organization that promotes hydrogen as an energy source in Europe
EnergyMap   www.energymap.dk
Danish internet portal for energy- and climate-related solutions
YouTube   www.youtube.com/watch?v=DCfMFSl90lA
The opening of Copenhagen's first hydrogen filling station
YouTube   www.youtube.com/watch?v=DO8Rc_YjJBk
Global TV report on renewable energy in Denmark, including electric car use in Copenhagen
Find out how a fuel cell works ...
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Copenhagen's first
hydrogen filling station
location  Hans Sydhavnen, Copenhagen
opened  12th November 2009
supplier  H2 Logic
refuelling capacity  5-10 vehicles per day
current hydrogen pressure  35,000kN per sq m
planned hydrogen pressure  70,000kN per sq m
The hydrogen supplied to Copenhagen's first filling station for vehicles is produced at a renewable energy facility, which electrolyses water into hydrogen and oxygen. The hydrogen is then pressurised into a liquid for delivery into the fuel cells of a vehicle. The cells recharge the vehicle's electric batteries continually as it travels, providing a range of 195-250km between fill-ups.
Other types of fuel cells
Polymer exchange membrane fuel cells
— operate at 60-80 degrees C
— heat up quickly
— most likely use: transport applications
Direct methanol fuel cells
— operate at 60-80 degrees C
— heat up quickly
— not as efficient as and usually more expensive than polymer exchange membrane cells
— most likely use: small portable devices
Solid oxide fuel cells
— operate at 700-1,000 degrees C
— co-generation of heat and power
— potential problems: design and reliability at high temperatures, material corrosion, expense
— most likely use: stationary power generation
Molten carbonate fuel cells
— operate at 600 degrees C
— co-generation of heat and power
— less expensive than solid oxide cells
— most likely use: stationary power generation
Phosphoric acid fuel cells
— operate at over 80 degrees C
— most likely use: stationary power generation
Alkaline fuel cells
— in use in USA since 1960s
— susceptible to contamination
— expensive
— unlikely to be of use commercially for now