ENG. Julius Ndirangu and Challenges and Opportunities in Grid Integration of Offshore Wind Farms – A Review Presenters ENG. Julius Ndirangu and ENG. STEPHEN NGULI ORGANIZATION Standards Department KENYA POWER Engineering Conference 2018

Engineering Conference 2018 Overview Introduction Design and Construction Considerations in Offshore Wind Farms Opportunities in Grid Integration of Offshore Wind Farms Challenges in Grid Integration of Offshore Wind Farms and Mitigation measures Conclusion Engineering Conference 2018

Engineering Conference 2018 Introduction Ocean economy - the economic activities that take place in the ocean, receive outputs from the ocean, and provide inputs to the ocean. Blue economy - sustainable ocean economy, where economic activity is in balance with the long-term capacity of ocean ecosystems to support this activity and remain resilient and healthy. Causes of Rapid Growth in Renewable Energy Production Rising cost of fossil fuels due to limited reserves Increase in demand for electrical energy Environmental issues caused by conventional sources Reduced costs of renewable energy generation installati0ns 178 GW of renewable power generation capacity added in 2017 globally. Engineering Conference 2018

Engineering Conference 2018 Introduction cont… Renewable energy sources from the ocean Ocean thermal energy conversion (OTEC), Wave energy, Tidal energy Offshore wind energy(OWFs). Why OWFs ? (i)Reduced space for installation of wind farms on land (ii) better energy production, (iii)reduced turbulence intensity, higher capacity factor . Currently, OWFs is visible in Europe & United States. Europe installed 16.8GW in 2017 net installed capacity to 168.7 GW: 153 GW onshore and 15.8 GW offshore Engineering Conference 2018

Engineering Conference 2018 Introduction cont… In 2005, it was found that Mozambique, Tanzania, Angola, South Africa and Namibia – have potentially large off-shore wind energy resources. In Kenya, a Swedish firm, VR Holding AB in 2016 expressed interest in building a 600MW wind farm in the Indian Ocean( Ras Ngomeni in Malindi.) Kenya government turned down the request citing (i)lack of a framework for renewable energy projects of that scale (ii)Low demand for electricity in the country. The investor moved to Tanzania Engineering Conference 2018

Design and Construction Considerations in OWFs An OWF comprises offshore wind turbines, a collector network system(2okV or 33kV), a step up substation and a transmission grid. Design and Construction considerations include: 1. OWF Installation - In the past fixed support platforms for wind turbine structures have been used. Disadvantage is high frequency excitation due to rotating blades and tower flexibility causes resonance to occur at its natural frequencies( shorten their fatigue life when the water depth increases.) Current trend is floating supported structures - have greater flexibility of construction and installation procedures and can be easily removed from the OWF system. Engineering Conference 2018

Design and Construction Considerations in OWFs cont.. 2. Power evacuation and Grid interconnection of Offshore Wind farms - Power evacuation from the OWFs to the onshore grid system is through Medium voltage/High voltage AC system or through a HVDC transmission system. Subsea AC power cables have a high capacitive shunt (less power transfer capability. DC system is preferred but is significantly expensive because of AC/DC/AC conversion. Engineering Conference 2018

Design and Construction Considerations in OWFs cont.. Typical layout of HVAC transmission system Engineering Conference 2018

Design and Construction Considerations in OWFs cont.. Typical layout of HVDC transmission system Engineering Conference 2018

Design and Construction Considerations in OWFs cont.. 3.OWF control and operation- Static synchronous compensator (STATCOM) for reactive power compensation for voltage control at the wind farm. Classical voltage and frequency droop characteristic for balanced active and reactive power. 4. Protection and security of OWFs - protection zones are wind farm area, collection system, interconnection system and the utility area. 5. Grid code compliance for OWFs : limits on voltage, total harmonic distortion (THD) level at PCC, FRT capability, frequency and voltage control. 6.Condition and Structural Health Monitoring of OWFs - Condition monitoring (CM) information in utilities is utilized to detect incipient faults, and thus enable to perform more effective and efficient maintenance scheduling. 7.Economics and ecological considerations in OWFs -The cost of electricity from OWFs is influenced by economic depreciation, operation and maintenance cost, tax paid to authorities, energy storage components as well as the intermittency factor due to variation in wind speed. Engineering Conference 2018

Opportunities in Grid Integration of Offshore Wind Farms Wind is much faster, stronger and, steady over water bodies than over land, resulting in increased power potential and efficiency. space availability in the ocean for installation of the turbines without interfering with populated areas. OWFs provide renewable energy(no pollutants or GHG). Employment in installation, operating, and maintaining offshore wind turbines than land-based ones. Global commitment to renewables :- focus on the immense stores of energy in the ocean. Engineering Conference 2018

Challenges in Grid Integration of OWFs and Mitigation measures Engineering Conference 2018

Challenges in Grid Integration of OWFs and Mitigation measures cont.. Engineering Conference 2018

Engineering Conference 2018 Conclusion Design and construction considerations for OWFs have been reviewed. Opportunities that stand to accrue from OWFs grid integration Challenges in Grid Integration of OWFs and possible mitigation measures suggested. Engineering Conference 2018

Engineering Conference 2018 Recommendations A pilot project to evaluate the viability of OWFs in Kenya through PPA to :- Develop a test bed to gather operating experience. Demonstrate technical reliability Verify commercial feasibility Engineering Conference 2018

Engineering Conference 2018 End Q & A THANK YOU Engineering Conference 2018